The invention relates to systems for managing electric batteries, and in particular systems for managing electric batteries installed on a motor vehicle and intended to propel said motor vehicle.
These batteries may be either recharged at electric terminals when the vehicle is stationary or recharged by recovering, by means of the electric motor, some of the kinetic energy of the vehicle when said vehicle decelerates. Such a recovery of energy is commonly referred to as regenerative braking.
The batteries may deteriorate or age and may lose their ability to store energy. This aging is dependent on the conditions in which the batteries have been stored and also on the conditions in which the batteries are used when a vehicle is moving.
Battery management systems (BMSs) which limit the amount of power provided to the battery so as not to damage said battery have been proposed. The currents circulating toward the battery or the voltages applied to the battery are thus limited. Furthermore, these limitations are generally calculated on the one hand for braking situations with energy recovery and on the other hand for normal charging situations, that is to say when the vehicle is stationary and a terminal is used.
The maximum power allowable by a battery in a braking situation is generally high and can be applied over a short period of approximately ten seconds without damaging the batteries. For charging (by means of a terminal), the power is generally weaker, but can be applied over a longer period.
When a user is in a long braking phase, for example during the descent of a long hill, braking with electric energy recovery of long duration can be implemented by using the limitation of high power of the braking phases. These long braking phases may damage the batteries of vehicles if they are longer than the 10 seconds corresponding to a normal braking phase. In fact, a high power will be provided to the battery during an excessively long period.
In addition, the power values are usually stored in mappings and can be read depending on the state of charge of the battery and the temperature of the battery. Two mappings can be used: one for each of the situations described above.